For a C-Corp, you must use TurboTax Business (different from Home & Business). TurboTax Business is not available as an online product, and is not available for MAC. Windows only. You can purchase TurboTax Business at https://turbotax.intuit.com/personal-taxes/cd-download/ by clicking the Corporation/partnership button and going from there.
Since this is your first year dealing with a C-Corp, I HIGHLY RECOMMEND that you seek the services of a tax professional in your local jurisdiction. Doing this wrong the first year can come back to bite you and the potential fines and penalties could easily bankrupt your business before it even gets off the ground. So the cost of a tax professional for this first year will be well worth it. Once you're past that first year tax filing, then you should be fine for following years doing it yourself, using that first year tax return for information and guidance.